WASHINGTON - An independent inquiry into the attack on the U.S. diplomatic mission in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans on Sept. 11, sharply criticized the State Department for a lack of seasoned security personnel and for relying on untested local militias to protect the compound, The New York Times reported on Tuesday.

The newspaper cited congressional and State Department officials for the report.

The committee investigating the incident, known as an Accountability Review Board and mandated by U.S. law, conducted its study in secret and presented its report to U.S. Secretary of State Hillary Clinton on Monday.

Clinton said on Tuesday she accepted the findings of an independent panel that faulted the State Department over the deadly September attack on the U.S. mission in Benghazi, Libya, and had ordered widespread changes to bolster U.S. diplomatic security overseas.

Clinton said in a letter to U.S. congressional committees that she had instructed the State Department to implement its findings "quickly and completely" and outlined a series of steps aimed at improving the security of U.S. diplomatic outposts.

The United States would send hundreds of additional Marine guards to overseas posts, ask for more money for security improvements and name a new State Department official to oversee "high threat posts," she said.